Field of the Invention
Described herein is a device relating to greenhouses, and specifically, adjustable endcaps for distribution tubes utilized in greenhouses.
Description of the Related Art
Greenhouses have been used for hundreds of years to grow different varieties of plants, including ornamental plants and fruit/vegetable-producing plants. Greenhouses typically comprise a structure with a plastic or glass roof and frequently glass or plastic walls. The interior of the greenhouse can be heated by incoming solar radiation that warms the plants and soil therein. The closed environment of a greenhouse has its own unique requirements, which may be different than those associated with outdoor plant growth compared with outdoor production. Pests and diseases need to be controlled and irrigation is necessary to provide water. Of equal importance, greenhouses can also be arranged to compensate for extreme highs and lows of heat and humidity, and to generally control the environmental conditions such as the level of carbon dioxide (CO2).
Different greenhouses have been developed to control the environmental conditions within the greenhouse. U.S. Pat. No. 5,001,859 to Sprung describes a method and structure for environmental control of plant growth in greenhouse conditions. The structure comprises a translucent stressed fabric shell on a base, which is configured to grow plants, the shell and base sealing the environment within the space against external environmental conditions. The temperature and relative humidity within the production areas are generally controlled by a microprocessor based series of spray systems, along with a furnace. The spray systems can lower the temperature in the space while at the same time increasing humidity, and the furnace can be utilized to increase the temperature within the space.
U.S. Pat. No. 5,813,168 to Clendening describes a greenhouse and a method for controlling the environment of the interior space within. The greenhouse includes an interior insulating panel and a movable exterior reflective panel capable of both insulating the interior of the greenhouse and reflecting sunlight into the interior. The greenhouse also includes a closed-system heat exchanger having a plurality of spaced water-impermeable water flow passageways through which water flows by gravitational forces, and having a means for blowing air between the water flow passageways such that the air does not contact the water and such that the air is either heated or cooled by the water. In addition, the heat exchanger may include a water and/or gas discharge for the control of humidity and gas levels within the greenhouse. Finally, the greenhouse includes hydroponic plant beds disposed on top of the heat exchangers and hydroponic solution tanks along the outer interior walls of the greenhouse.
U.S. Pat. No. 7,228,657 to Brault et al. discloses a greenhouse having an exterior curtain wall structure formed by spaced tubular posts carrying external transparent panels and bottom non-transparent wall panels below a sill, with the panels spanning the posts. A plurality of elongate benches is located within the interior at spaced positions along one side wall, with the width of the benches being equal to the post spacing to form an expandable construction. Each bench has associated with it a respective air handling system for conditioning, including a duct which is located partly under the respective bench and a fan in a fan housing at the side wall. From the fan, a vertical duct section extends to a flexible tube extending over the bench.
Typically, greenhouse distribution conduits, such as tubing, distribute substances such as air or gas along the length of the conduit via perforations or other means, and are otherwise closed at the end of the conduit which is inside the growing section of the greenhouse. An example of such a sealed greenhouse distribution conduit is set forth in U.S. Pat. No. 4,292,762 to Fogg, et al. By sealing this end, the distribution integrity along the length of the conduit can be better maintained, and unequal distribution—which would otherwise occur at the location of the greenhouse growing section near the open end of the distribution conduit—can be prevented. Such means for closing the ends of distribution tubes include the use of a knotted cover, such as a plastic cover, or a permanent means of sealing, such as welding, which forms a closed capsule. However, these arrangements provide only a fixed solution to sealing the ends of the distribution tubes and do not allow for any additional control or regulation of the conduits.